ITMI20010546A1 - COMPOUNDS OF 2,2,6,6-DIETHYL-1-ALCOSSIPIPERIDINE AND THEIR CORRESPONDENTS 1-OXIDES - Google Patents

Description

DESCRIPTION OF THE INDUSTRIAL INVENTION

The present invention relates to derivatives of 1-alkoxy-2, 2, -diethyl-6, 6-dimethylpiperidine and of 1-alkoxy-2, 6-diethyl-2, 3,6-trimethylpiperidine which are substituted in position 4 with an atom of oxygen or with a nitrogen atom; it relates to a polymerizable composition comprising a) at least one ethylenically unsaturated monomer and b) said piperidine derivatives. Further aspects of the present invention are a process for the polymerization of ethylenically unsaturated monomers and the use of 1-alkoxy-2, 2-diethyl-6,6-dimethylpiperidine derivatives and 1-alkoxy-2,6-diethyl derivatives -2,3,6-trimethylpiperidines which are substituted in position 4 with an oxygen atom or with a nitrogen atom to effect a controlled polymerization. The intermediate N-oxyl derivatives, a composition of the oxyl derivatives with ethylenically unsaturated monomers and a free radical initiator and also a polymerization process are also the object of the present invention. The compounds of the present invention provide polymeric resins having a poor polydispersibility. The polymerization process proceeds with a good transformation efficiency from monomer to polymer. In particular, the present invention relates to polymerization processes favored by stable free radicals which lead to obtain homopolymers, copolymers with random distribution, block copolymers, multiblock copolymers, graft copolymers and the like, with considerable polymerization speeds and with considerable degrees of transformation from monomer to polymer.

US-A 581 429 to Solomon et al, issued April 8, 1986, discloses a free radical polymerization process that controls the growth of polymer chains to produce homopolymers and short-chain or oligomeric copolymers, including graft blocks and copolymers. The process employs an initiator having the formula (in part) R'R "N-0-X, in which X is a free radical species capable of polymerizing unsaturated monomers. Typically, the reactions have low degrees of transformation. Radical groups R'R "N-0 · particularly cited are derivatives of 1, 1,3,3-tetraethylisoindoline, 1,1,3,3-tetrapropylisoindoline, 2,2,6,6-tetramethylpiperidine, 2,2,5,5 -tetramethylpyrrolidine or di-t-butylamine. However, the suggested compounds do not meet all requirements. In particular, the polymerization of acrylates does not proceed quickly enough and / or the degree of transformation from monomer to polymer is not sufficiently high as would be desirable.

Recently, other studies have been published to develop novel polymerization regulating agents. WO 98/4408 and WO 98/30601 describe heterocyclic compounds suitable for controlled polymerization processes. WO 98/13392 describes open chain alkoxyamines which derive from gaseous NO or from nitrous derivatives.

GB 2335190 discloses polymerization regulators / polymerization initiators based on 2,2,6,6-tetraalkylpiperidines, in which the alkyl groups have from 1 to 6 carbon atoms and, at least one group, is different from methyl.

It has been found that, among these 2, 2,6,6-tetraalkylpiperidines, generally described in GB 2335190, those which are derivatives of 1-alkoxy-2, 2-diethyl-6, 6-dimethylpiperidine and 1- alkoxy-2, 6-diethyl-2, 3, 6-trimethylpiperidine and which are substituted in position 4 with an oxygen atom or with a nitrogen atom which, in turn, is further substituted. The steric hindrance introduced by the two diethyl groups leads to an optimized equilibrium in terms of compound stability, initial activity and polymerization control.

The particular substitution model in position 2 and position 6 of the piperidine ring allows high degrees of transformation from monomer to polymer in short times and low polydispersibility which, in general, are less than 2. High degrees of transformation from monomer to polymer are also obtained with acrylates, for example ethyl acrylate or butyl acrylate. The temperatures necessary to obtain a high transformation in a short time can be low, for example 120 ° C.

The compounds show an unaltered initiation / regulation activity even after storage at high temperatures, for example adopted in traditional stability tests.

The oxygen atom or the nitrogen atom at position 4 of the piperidine ring allows for a variety of substitutions. This can be done, for example, to regulate secondary properties, for example the polarity of the compounds and therefore their compatibility with mixtures of monomers, oligomers and polymers or their volatility.

An object of the present invention is a compound of formula la or 11a

in which

Y is a radical

R-L is hydrogen, -COOH, -C00 (C1-C4alkyl), -COO-phenyl, -COObenzyl, -C1-C8alkoxy, C1-C18alkyl, C2-C4alkenyl, C1-C18alkyl or C2-C4alkenyl substituted with OH, -COOH, -COO (C1-C4) alkyl, C2-C18alkyl, which can be interrupted with one or more atoms of oxygen, cyclopentyl, cyclohexyl, cyclohexenyl, phenyl or unsubstituted naphthyl; or cyclopentyl, cyclohexyl, cyclohexenyl, phenyl or naphthyl which are substituted with C1-C4alkyl, -COOH or -COO- (C1-C4alkyl); R2 is hydrogen, C1-C18alkyl or R1 and R2, together with the nitrogen atom, form a 5-membered ring which can have an unsaturated bond or can be fused to a benzene ring;

R3 is hydrogen or C1-C18alkyl; And

X is selected from the group consisting of - (C5-C12) -3-cycloalkenyl, -CH2-phenyl, -CH3CH-phenyl, (CH3) 2C-phenyl, (C5-C6cycloalkyl) 2CCN, (CH3) 2CCN, -CH2CH = CH2, CH3CH-CH = CH2, (C1-C4alkyl) CR20-C (0) -phenyl, (C1-C4alkyl-CR20-C (0) - (C1-C4) alkoxy, (C1-C4) alkyl-CR20- C (0) - (C1-C4) alkyl, (C1-C4) alkyl-CR20-C (0) -N-di (C1-C4) alkyl, (C1-C4) alkyl-CR20-C (0) - NH (C1-C4) alkyl, (C1-C4) alkyl-CR20-C (0) -NH2, wherein R20 is hydrogen or (C1-C4) alkyl; with the proviso that 2, 6-diethyl- 2, 3, 6-trimethyl-1- (1-phenyl-ethoxy) -piperidin-4-ylester of benzoic acid.

C1-C18alkyl can be linear or branched. Examples are methyl, ethyl, propyl, isopropyl, butyl, 2-butyl, isobutyl, t-butyl, pentyl, 2-pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, t-octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, hexadecyl and octadecyl.

Examples of C2-C18alkyl interrupted with -0-are, for example, 3-oxapentane, 4-oxoheptane, 3,6-dioxoctane, 4,7-dioxadecane, 4,9-dioxadodecane, 3,6, 9-triossaundecane and 4 , 7,10-trioxatridecane.

Alkyl substituted with a -COOH group is, for example, CH2-COOH, CH2-CH2-COOH, (CH2) 3-COOH or CH2-CHCOOH-CH2-CH3.

Examples of alkoxy groups containing no more than 8 carbon atoms are methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, pentoxy, isopentoxy, hexoxy, heptoxy or octoxy.

C2-C4alkenyl is, for example, ethenyl, propenyl or butenyl; preferably it is ethenyl or it is -C (CH3) = CH2.

Cyclohexyl substituted with COOH is, for example, cyclohexane-carbonic acid.

Phenyl substituted with COOH is, for example, benzoic acid.

Phenyl substituted with C1-C4alkyl is, for example, toluene or xylene.

Preferably, X is -CH2-phenyl, CH3CH-phenyl,

(3-cyclohexenyl) or (CH3) 2C-phenyl.

More preferably X is CH3CH-phenyl.

Preferred compounds are of formula la or 11a wherein Y is a radical of formula

and it has the meaning

indicated above.

Particularly preferred are the following single compounds.

Compounds according to the formula (la).

The compounds according to formulas Ia and IIa can be prepared according to standard methods.

The 4-OH intermediates are prepared as described in GB 2335190.

If Y is -C (0) -R1 or 0 (0) -ΝΗ-R1, the 4-OH intermediates are reacted with the desired derivatives of carbonic acid or with isocyanates according to the general scheme outlined below.

The following compounds are most preferred: (1) 2, 6-diethyl-2,3,6-trimethyl-1- (1-phenyl-ethoxy) -piperidin-4-yl-ester of formic acid; (2) 2,6-diethyl-2,3,6-trimethyl-1- (1-phenyl-ethoxy) -piperidin-4-yl ester of acetic acid; (3) 2,6-diethyl-2,3,6-trimethyl-1- (1-phenyl-ethoxy) -piperidin-4-yl ester of propionic acid; (4) 2,6-diethyl-2,3,6-trimethyl-1- (1-phenyl-ethoxy) -piperidin-4-yl ester of butyric acid; (5) 2,6-diethyl-2,3,6-trimethyl-1- (1-phenyl-ethoxy) -piperidin-4-ylester of pentanoic acid; (6) 2, 6-diethyl-2,3,6-trimethyl-1- (1-phenyl-ethoxy) piperidine-4-yl ester of hexanoic acid; (7) 2,6-diethyl-2, 3,6-trimethyl-1- (1-phenyl-ethoxy) -piperidin-4-yl-ester of heptanoic acid; (8) 2,6-diethyl-2,3,6-trimethyl-1- (1-phenyl-ethoxy) -piperidin-4-yl ester of octanoic acid; (9) 2,6-diethyl-2, 3,6-trimethyl-1- (1-phenyl-ethoxy) -piperidin-4-yl-ester of nonanoic acid; (10) 2,6-diethyl-2, 3,6-trimethyl-1- (1-phenyl-ethoxy) -piperidin-4-yl ester of decanoic acid; (11) 2,6-diethyl-2,3,6-trimethyl-1- (1-phenyl-ethoxy) -piperidin-4-yl-ester of undecanoic acid; (12) 2,6-diethyl-2, 3,6-trimethyl-1- (1-phenyl-ethoxy) -piperidin-4-yl ester of dodecanoic acid; (13) 2,6-diethyl-2,3,6-trimethyl-1- (1-phenyl-ethoxy) -piperidin-4-yl-ester of tridecanoic acid; (14) 2,6-diethyl-2,3,6-trimethyl-1- (1-phenyl-ethoxy) -piperidin-4-yl ester of tetradecanoic acid; (15) 2,6-diethyl-2,3,6-trimethyl-1- (1-phenyl-ethoxy) -piperidin-4-ylester of pentadecanoic acid; (16) 2,6-diethyl-2, 3,6-trimethyl-1- (1-phenyl-ethoxy) -piperidin-4-yl-ester of hexadecanoic acid; (17) 2,6-diethyl-2,3,6-trimethyl-1- (1-phenyl-ethoxy) -piperidin-4-yl ester of heptadecanoic acid; (18) 2,6-diethyl-2,3,6-trimethyl-1- (1-phenyl-ethoxy) -piperidin-4-yl ester of octadecanoic acid; (19) 2,2-diethyl-6, 6-dimethyl-1- (1-phenyl-ethoxy) -piperidin-4-yl ester of formic acid;

(20) 2,2-diethyl-6, 6-dimethyl-1- (1-phenyl-ethoxy) -piperidin-4-yl ester of acetic acid;

(21) 2,2-diethyl-6, 6-dimethyl-1- (1-phenyl-ethoxy) -piperidin-4-yl ester of propionic acid; (22) 2,2-diethyl-6, 6-dimethyl-1- (1-phenyl-ethoxy) -piperidin-4-yl ester of butyric acid; (23) 2,2-diethyl-6, 6-dimethyl-1- (1-phenyl-ethoxy) -piperidin-4-yl ester of pentanoic acid; (24) 2,2-diethyl-6,6-dimethyl-1- (1-phenyl-ethoxy) -piperidin-4-yl ester of hexanoic acid; (25) 2,2-diethyl-6, 6-dimethyl-1- (1-phenyl-ethoxy) -piperidin-4-yl ester of heptanoic acid; (26) 2,2-diethyl-6, 6-dimethyl-1- (1-phenyl-ethoxy) -piperidin-4-yl ester of octanoic acid; (27) 2,2-diethyl-6, 6-dimethyl-1- (1-phenyl-ethoxy) -piperidin-4-yl ester of nonanoic acid; (28) 2, 2-diethyl-6,6-dimethyl-1- (1-phenyl-ethoxy) -piperidin-4-yl ester of decanoic acid; (29) 2,2-diethyl-6, 6-dimethyl-1- (1-phenyl-ethoxy) -piperidin-4-yl ester of undecanoic acid; (30) 2,2-diethyl-6, 6-dimethyl-1- (1-phenyl-ethoxy) -piperidin-4-yl ester of dodecanoic acid; (31) 2,2-diethyl- 6,6-dimethyl-1- (1-phenyl-ethoxy) piperidine-4 -yl ester of tridecanoic acid; (32) 2,2-diethyl - 6, 6 -dimethyl-1- (1-phenyl-ethoxy) -piperidin-4- -yl ester of tetradecanoic acid; : 33) 2, 2-diethyl-6, 6-dimethyl-1- (1-phenyl-ethoxy) -piperidin-4 -yl ester of pentadecanoic acid; : 34) 2, 2-diethyl-6, 6-dimethyl-1- (1-phenyl-ethoxy) -piperidin-4 -yl-ester of hexadecanoic acid; (35) 2,2-diethyl - 6, 6-dimethyl-1- (1-phenyl-ethoxy) -piperidin-4 -yl ester of heptadecanoic acid; (36) 2, 2-diethyl-6, 6-dimethyl-1- (1-phenyl-ethoxy) -piperidin-4 -yl ester of octadecanoic acid;

The 4-amino, 1-oxyl-intermediates are prepared, for example, by reducing amination of the corresponding 4-oxo-compound which in turn is prepared as described in GB 2335190.

If Y is -NR3-C (0) -R1 or -NR3-C (0) -NHR1, the 4-amino- or 4-alkylamino-compounds are reacted with carbonic acid derivatives (chloride, anhydride or an ester of carbonic acid) or with isocyanates. It is also possible to start from the corresponding piperidine compounds and oxidize the intermediates to the corresponding N-oxides. This reaction is described, for example, in US 4 191 683. The nitroxides are then transformed into the corresponding alkoxyamines as described in GB 2335190.

This process is schematically outlined below:

If Y is R1-C (0) -N— C (0) -R2, the preparation is carried out according to US 4 191 683, starting from the corresponding 4- (alkyl) aminopiperidino compounds.

A further object of the invention relates to a

polymerizable composition comprising a) at least one ethylenically unsaturated monomer or oligomer, and

b) a compound of formula la or la

in which

Y is a radical

R1 is hydrogen, -COOH, -C00 (C1-C4alkyl), -COO-phenyl, -COObenzyl, C1-C8alkoxy, C1-C18alkyl, C2-C4alkenyl, C1-C18alkyl or C2-C4alkenyl substituted with OH, -COOH, - C00 (C1-C4) alkyl, C2-C18alkyl which can be interrupted with one or more oxygen atoms, cyclopentyl, cyclohexyl, cyclohexenyl, phenyl or naphthyl unsubstituted or cyclopentyl, cyclohexyl, cyclohexenyl, phenyl or naphthyl which are substituted with C1- C4alkyl, -COOH or with -C00- (C1-C4alkyl); R2 is hydrogen, C1-C18alkyl or R1 and R2, together with the nitrogen atom, form a 5-membered ring

which can have an unsaturated bond or can be condensed with a benzene ring;

R3 is hydrogen or C1-C18alkyl; And

X is selected from the group consisting of - (C5-C12) -3-cycloalkenyl, -CH2-phenyl, CH3CH-phenyl, (CH3) 2C-phenyl, (C5-C6cycloalkyl) 2CCN, (CH3) 2CCN, -CH2CH = CH2 , CH3CH-CH = CH2, (C1-C4alkyl) CR20-C (0) -phenyl, (C1-C4) alkyl-CR20-C (0) - (C1-C4) alkoxy, (C1-C4) alkyl-CR20 -C (0) - (C1-C4) alkyl, (C1-C4) alkyl-CR20-C (0) -N-di (C1-C4) alkyl, (C1-C4) alkyl-CR20-C (0) -NH (C1-C4) alkyl, (C1-C4) alkyl-CR20-C (O) -NH2, wherein R20 is hydrogen or (C1-C4) alkyl; with the proviso that 2, 6-diethyl-2, 3, 6-trimethyl-1- (1-phenyl-ethoxy) -piperidin-4-yl-ester of benzoic acid is excluded.

Definitions for substituents and preferred formulas have already been reported. These also apply to the composition which includes the preferred meanings.

Typically, the ethylenically unsaturated monomer or oligomer is selected from the group consisting of ethylene, propylene, n-butylene, i-butylene, styrene, substituted styrene, conjugated dienes, acrolein, vinyl acetate, vinylpyrrolidone, vinylimidazole, maleic anhydride, (alkyl) acrylic acid, salts of an (alkyl) acrylic acid, esters (), (meth) acrylonitriles, (alkyl) acrylamides, vinyl halides or vinylidene halides.

Preferred ethylenically unsaturated monomers are ethylene, propylene, n-butylene, i-butylene, isoprene, 1, 3-butadiene, α-C5-C18alkene, styrene, a-methyl-styrene, p-methyl-styrene or a compound of formula CH2 = C (Ra) - (C = Z) -Rb, where Ra is hydrogen or C1-C4, Rb is NH2, 0 <-> (Me <+>), glycidyl, unsubstituted C1-C18alkoxy, C2-C100alkoxy interrupted with at least one nitrogen and / or oxygen atom, or C1-C18 alkoxy hydroxy-substituted, C1-C18 alkylamino, unsubstituted (C1-C18alkyl) amino, C1-C18 hydroxy-substituted alkylamino or (C1-C18 alkyl ) amino hydroxy-substituted, -0-CH2-CH2-N (CH3) 2 or -0-CH2-CH2-N <+> H (CH3) 2 An <_>;

An <-> is an anion of a monovalent organic or inorganic acid;

Me is an atom of a monovalent metal or the ammonium ion;

Z is oxygen or sulfur.

Examples of Ra such as C2-C100alkoxy interrupted with at least one oxygen atom are of formula

wherein Rc is C1-C25alkyl, phenyl or phenyl substituted with C1-C18alkyl, Rd is hydrogen or methyl and v is a number between 1 and 50. These monomers, for example, are derived from non-ionic surfactants by acrylation of the corresponding alcohols or alkoxylated phenols. The recurring units can be derived from ethylene oxide, propylene oxide or mixtures thereof.

Further examples of suitable acrylate or methacrylate monomers are given below:

where An <-> and Ra have the meaning as defined above and Re is methyl or benzyl. An <-> is preferably Cl-, Br <-> or -O3S-CH3.

Further acrylate monomers are

Examples of suitable monomers other than acrylates are

Preferably Ra is hydrogen or methyl Rb is NH2, glycidyl, unsubstituted or hydroxy-substituted C1-C4alkoxy, Cl -C4a1kylamino, unsubstituted di (C1-C4alkyl) amino, C1-C4alkylamino hydroxy-substituted or di (C1-C4alkyl) amino hydroxy substituted; And

Z is oxygen.

Particularly preferred ethylenically unsaturated monomers are styrene, methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, tert-butyl acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, dimethylithiminoethyl acrylate, glycidyl acrylates, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (methyl) acrylate, butyl (methyl) acrylate acrylate, hydroxypropyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, glycidyl (meth) acrylates, acrylonitrile, acrylamide, methacrylamide or dimethylaminopropyl-methacrylamide.

Preferably, the initiator compound is present in an amount of between 0.01 mol% and 30 mol%, more preferably in an amount of between 0.1 mol% and 20 mol% and most preferably in an amount between 0.1 mole% and 10 mole% referred to the monomer or to the mixture of monomers.

When using mixtures of monomers, the moles% are calculated on the average molecular weight of the mixture.

Another object of the present invention is a process for preparing an oligomer, a cooligomer, a polymer or a copolymer (block or random) by means of free radical polymerization of at least one monomer or an ethylenically unsaturated oligomer, which consists in making (co) polymerize the monomer or monomers / oligomers in the presence of the initiator compound of formula la or 11a in the reaction conditions suitable for carrying out the cleavage of the C-O bond, so as to form two free radicals, the radical Χ being able to initiate the polymerization.

Preferably, the cleavage of the C-0 bond is carried out by ultrasonic treatment, by heating or by exposure to an electromagnetic radiation ranging from γ-rays to microwaves.

More preferably, the cleavage of the C-0 bond is carried out by heating and takes place at a temperature between 50 ° C and 160 ° C.

The process can be carried out in the presence of an organic solvent or in the presence of water or in mixtures of organic solvents and water. Further co-solvents or surfactants may be present, for example glycols or ammonium salts of fatty acids. Other suitable co-solvents are described below.

In preferred processes, the smallest possible amount of solvents is used. In the reaction mixture it is preferred to use more than 30% by weight of monomer and initiator, particularly more preferably more than 50% and most preferably more than 80%.

If organic solvents are used, suitable solvents or suitable solvent mixtures typically consist of pure alkanes (hexane, heptane, octane, hexocarbon), hydrocarbons (benzene, toluene, xylene), halogenated hydrocarbons (chlorobenzene), alkanols (methanol, ethanol, ethylene glycol, ethylene glycol monomethyl ether), esters (ethyl acetate, propyl, butyl or hexyl acetate) and ethers (diethyl ether, dibutyl ether, ethylene glycol dimethyl ether) or mixtures thereof.

The aqueous polymerization reaction mixtures can be supplemented with a water-miscible or hydrophilic co-solvent to help ensure that the reaction mixture remains a single homogeneous phase throughout the transformation of the monomers. Any water-soluble or water-miscible co-solvent may be used, provided the aqueous solvent medium is effective in producing a solvent system that prevents precipitation or phasing of reactants or polymer products until they have been all polymerization reactions completed. Exemplary co-solvents useful in the present invention can be selected from the group consisting of aliphatic alcohols, glycols, ethers, glycolethers, pyrrolidines, N-alkylpyrrolidinones, N-alkylpyrrolidones, polyethylene glycols, polypropylene glycols, amides, carboxylic acids and their salts, esters, organic sulphides , sulfoxides, sulfones, derivatives of alcohols, derivatives of hydroxyethers such as butylcarbitol or cellosolves, amino-alcohols, ketones and the like and also their derivatives and their mixtures. Specific examples include methanol, ethanol, propanol, dioxane, ethylene glycol, propylene glycol, diethylene glycol, glycerol, dipropylene glycol, tetrahydrofuran or other water-soluble or water-miscible compounds and mixtures thereof. When mixtures of water and water-soluble or water-miscible organic liquids are selected as the aqueous reaction media, the weight ratio of water to co-solvent typically ranges from about 100: 0 to about 10:90.

The process is particularly useful for the preparation of block copolymers.

Block copolymers are, for example, block copolymers of polystyrene and polyacrylate, for example poly (styrene-co-acrylate) or poly (styrene-co-acrylate-styrene). They are useful as adhesives or as compatibilizing agents for polymer blends or as agents that impart toughness to polymers. Two-block poly (methyl methacrylate-coacrylate) copolymers or three-block poly (methyl acrylate-co-acrylate-co-methacrylate) copolymers are useful as dispersing agents for a coating system, as coatings additives (e.g. rheological agents, compatibilizers, reactive diluents) or as a resin component in coatings (for example paints with high solids content). Block copolymers of styrene, (meth) acrylates and / or acrylonitrile are useful for plastics, elastomers and adhesives.

Furthermore, the block copolymers of this invention in which the blocks are alternated between polar monomers and non-polar monomers, are useful in many applications as amphiphilic surfactants or dispersants for preparing highly uniform polymer blends.

The (co) polymers of the present invention can have a number average molecular weight comprised between 1,000 and 400,000 g / mol, preferably between 2,000 and 250,000 g / mol and, more preferably, between 2,000 and 200,000 g / mol. When polymers are mass produced, the number average molecular weight goes up to 500,000 (the minimum weights being the same as those mentioned above). The number average molecular weight can be determined by size exclusion chromatography (SEC), by gel permeation chromatography (GPC), by matrix-assisted laser desorption / ionization mass spectrometry (MALDI-MS) or, if the initiator carries a group which can be easily differentiated from the monomer (s), by NMR spectroscopy or by other conventional methods.

The polymers or copolymers of the present invention preferably have a polydispersibility between 1.0 and 2, more preferably between 1.1 and 1.9 and most preferably between 1.1 and 1.8.

Thus, the present invention further comprises in the synthesis novel block, multi-block, star, gradient, random distribution, hyper-branched and dendritic copolymers and also graft copolymers.

The polymers prepared by the present invention are useful for the following applications:

adhesives, detergents, dispersants, emulsifiers, surfactants, defoamers, substances that promote adhesion, corrosion inhibitors, substances that improve viscosity, lubricants, substances that modify rheology, thickeners, crosslinkers, substances for the treatment of paper , for water treatment, such as electronic materials, paints, coatings, photographic materials, ink materials, image recording materials, super absorbents, cosmetic products, hair products, preservatives, biocides or modifying agents for asphalt, leather, textiles, ceramic and wood products.

Since the polymerization of the present invention is a "living" polymerization, it can be initiated and stopped practically at will. Furthermore, the polymeric product retains the functional alkoxy amino group which allows a continuation of the polymerization in a living substance. Thus, in one embodiment of this invention, once the first monomer has been consumed in the initial stage of polymerization, a second monomer can then be added to form a second block on the growing polymer chain in a second stage. of polymerization. Therefore, it is possible to carry out further polymerizations with the same monomer or with different monomers to prepare multiblock copolymers. Also, since this is radical polymerization, blocks can be prepared in any essential order. One is not necessarily limited to preparing block copolymers in which the sequential polymerization steps must flow from the less stabilized polymer intermediate towards the more stabilized polymer intermediate as in the case of an ionic polymerization. Thus, it is possible to prepare a multi-block copolymer in which a block of polyacrylonitrile or a poly (meth) acrylate is first prepared, then a block of styrene or butadiene, etc. is connected.

Furthermore, no linking assembly is required to connect the different copolymer blocks of the present invention. One can simply add successive monomers to form successive blocks.

By means of the present invention, several specifically indicated polymers and copolymers are accessible, for example star and graft (co) polymers as described inter alia by C. J. Hawker in Angew. Chemie, 1995, 107, p. 1623-1627, dendrimers as described by K. Matyaszewski et al. in Macromolecules 1996, Vol. 29, No. 12, p. 4167-4171, graft (co) polymers as described by C. J. Hawker et al. in Macromol. Chem. Phys. 198, 155-166 (1997), randomly distributed copolymers as described by C. J. Hawker et al. in Macromolecules 1996, 29, 2686-2688, or two-block and three-block copolymers as described by N. A. Listigovers in Macromolecules 1996, 29, 8992-8993.

A further object of the present invention is a polymer or an oligomer, having connected at least one initiator group -X and at least one group of an oxyamine of formula la or 11a.

The compounds of formula la and 11a can be prepared from the corresponding nitroxides, which are intermediate products for the compounds of formula la and 11a.

Still a further object of the present invention are nitroxides of formula IIa and IVa

in which

Y is a radical

R-L is hydrogen, -COOH, -C00 (C1-C4alkyl), -COO-phenyl, -COObenzyl, -C1-C8alkoxy, C1-C18alkyl, C2-C4alkenyl, C1-C18alkyl or C2-C4alkenyl substituted with OH, -C00 H , -C00 (C1-C4) alkyl, C2-C18alkyl, which can be interrupted with one or more oxygen atoms, cyclopentyl, cyclohexyl, cyclohexenyl, phenyl or unsubstituted naphthyl; or cyclopentyl, cyclohexyl, cyclohexenyl, phenyl or naphthyl which are substituted with C1-C4alkyl, -COOH or -COO- (C1-C4alkyl); R2 is hydrogen, C1-C18alkyl or and R2, together with the nitrogen atom, form a 5-membered ring which can have an unsaturated bond or can be fused to a benzene ring;

R3 is hydrogen or C1-C18alkyl; with the proviso that 2, 6-diethyl-2, 3, 6-trimethyl-4-lauroyloxypiperidin-1-oxyl, 2, 6-diethyl-2, 3, 6-trimethyl-4-stearoyloxypiperidin- 1,2-dimethyl-6, 6-diethyl-4-lauroyloxypiperidin-1-oxyl and 2,2-dimethyl-6, 6-diethyl-4-stearoyloxypiperidin-1-oxyl.

Definitions for the substituents and also their preferences have already been indicated above. They apply to the compounds of formula IIa and IVa.

Particularly preferred are single compounds according to the formulas la and 11a, indicated above, for which the corresponding N-oxides are precursors, which therefore are of particular interest.

The compounds of formula IIa and IVa are also particularly useful for controlled polymerization reactions in combination with a source of free radicals.

The object of the present invention is also a polymerizable composition which comprises:

a) at least one ethylenically unsaturated monomer or oligomer, e

b) a compound of formula IIIa or IVa e

c) a source of free radicals capable of initiating a polymerization of ethylenically unsaturated monomers.

The production of C-centered radicals is described, for example, in Houben Weyl, Methoden der Organischen Chemie, Vol. E 19a, p. 60-147. These methods can be generally implemented in a similar way.

The radical source can be a bis-azo compound, a peroxide or a hydroperoxide.

Preferably, the radical source is 2, 2 '-azobisisobutyronitrile, 2, 2' -azobis (2-methylbutyronitrile), 2, 2 '-azobis (2, 4-dimethylvaleronitrile), 2,2' -azobis (4-methoxy -2, 4-dimethylvaleronitrile), 1, 1 '-azobis (1-cyclohexanecarbonitrile, 2, 2' -azobis (isobutyramide) dihydrate, 2-phenylazo-2, 4-dimethyl-4-methoxivaleronitrile, dimethyl-2, 2 ' -azobisisobutyrate, 2- (carbammoylazo) isobutyronitrile, 2,2 '-azobis (2,4,4 - trimethylpentane), 2,2' -azobis (2-methylpropane), 2, 2 '-azobis (N, N' -dimethylenisobutyramide), free base or hydrochloride, 2, 2 '-azobis (2-amidinopropane), free base or hydrochloride, 2, 2' -azobis {2-methyl-N- [1, 1-bis (hydroxymethyl) ethyl] propionamide} or 2,2'azobis {2-methyl-N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] -propionamide}.

Preferred peroxides and hydroperoxides are acetylcyclohexane-sulfonyl-peroxide, diisopropyl-peroxydicarbonate, t-amyl-perneodecanoate, t-butyl-perneodecanoate, t-butyl-perpivalate, t-amyl-perpivaiate, bis (2,4-dichlorobenzoyl) -peroxide, diisononano , didecanoyl-peroxide, dioctanoyl-peroxide, dilauroyl-peroxide, bis (2-methylbenzoyl) -peroxide, disuccinic acid peroxide, diacetyl peroxide, dibenzoyl peroxide, t-butyl-per-2-ethylhexanoate, bis- (4 -chlorobenzoyl) -peroxide, t-butyl-perisobutyrate, t-butyl-permaleinate, 1,1-bis (t-butylperoxy) -3,5,5-trimethylcyclohexane, 1,1-bis (t-butyl-peroxy) - cyclohexane, t-butyl-peroxy-isopropyl-carbonate, t-butylperisononanoate, 2,5-dimethylhexane-2, 5-dibenzoate, t-butyl-peracetate, t-amyl-perbenzoate, t-butylperbenzoate, 2,2-bis - (t-butylperoxy) -butane, 2,2-bis- (t-butyl-peroxy) -propane, dicumyl-peroxide, 2,5-dimethylhexane-2,5-di-t-butyl-peroxide, 3-t -butylperoxy-3-phenylphthalide, di-t-amyl-peroxide, a, a '-bis (t-butyl-pe red-isopropyl) -benzene, 3,5-bis- (t-butyl-peroxy) -3,5-dimethyl-1,2-dioxolane, di-tbutyl-peroxide, 2,5-dimethylhexino-2,5-di -t-butyl peroxide, 3, 3,6,6, 9,9-hexamethyl-1, 2,4,5-tetraoxacyclononane, p-menthane-hydroperoxide, pinane-hydroperoxide, diisopropylbenzene-mono-a-hydroperoxide, cumene-hydroperoxide or t-butyl-hydroperoxide.

These compounds are commercially available. If more than one source of radicals is used, a mixture of substitution patterns can be obtained.

The source of radicals is preferably present in an amount comprised between 0.01 mol% and 30 mol%, more preferably in an amount comprised between 0.1 mol% and 20 mol% and most preferably in an amount comprised between 0.5 mole% and 10 mole% referred to the monomer or to the mixture of monomers.

The molar ratio of the radical source with respect to the compound of formula II can be comprised between 1: 10 and 10: 1, preferably between 1: 5 and 5: 1 and more preferably between 1: 2 and 2: 1.

Still another object of the present invention is a process for preparing an oligomer, a cooligomer, a polymer or a copolymer (in blocks or with random distribution) by free radical polymerization of at least one ethylenically unsaturated monomer / oligomer, which consists in subjecting the above composition to a thermal treatment or to an actinic radiation.

Further objects of the present invention are the use of a compound of formula la or 11a

for the polymerization of ethylenically unsaturated monomers and the use of a compound of formulas Illa or IVa

together with a source of free radicals for the polymerization of an ethylenically unsaturated monomer.

Definitions and preferences for the different substituents have already been indicated with respect to the initiator compounds. They also apply to other objects of the present invention, including preferences and single compounds.

The following examples illustrate the present invention.

Example A1: 2,6-diethyl-2,3,6-trimethyl-1- (1-phenyl-ethoxy) -piperidin-4-yl-ester of acetic acid (Formula la, Compound 2)

To a solution of 6.36 g (2 mmol) of 2,6-diethyl-2,3,6-trimethyl-1- (1-phenyl-ethoxy) -piperidin-4-ol (prepared as described in GB 2335190, Example 7, Compound 102) and 2.02 g (2 mmoles) of triethylamine in 50 ml of toluene, 1.57 g (2 mmoles) of acetyl-chloride at 0-5 ° C are added and the mixture of reaction for 2 hours at 20 ° C. The reaction mixture is then extracted several times with water. The organic phase is dried on Na2SO4 and, after removal of the solvent, 6.9 g (96%) of 2,6-diethyl-2,3,6-trimethyl-1- (1-phenylethoxy) -piperidin-4 are obtained -the ester of acetic acid in the form of a yellow liquid.

Elemental analysis calculated for C22H35NO3: C 73.0%; H 9.76%; N 3.87%. Found: C 72.87%; H 9.64%; N 3.85%.

Example A2: 2,6-diethyl-2,3,6-trimethyl-1- (1-phenyl-ethoxy) -piperidin-4-yl-ester of acrylic acid (Formula 1a, Compound 39)

In analogy to Example 1 6, 36 g (2 mmoles) of 2, 6-diethyl-2, 3, 6-trimethyl-1- (1-phenyl-ethoxy) -piperidin-4-ol were reacted with 1, 81 g (2 mmol) of acryloyl chloride and with 2, 02 g (2 mmol) of triethylamine in toluene thus obtaining 6.5 g (87%) of 2, 6-diethyl-2, 3, 6-trimethyl -l- (1-phenyl-ethoxy) -piperidin-4-yl-ester of acrylic acid in the form of a yellow liquid.

Elemental analysis calculated for C23H35NO3: C 73.95%; H 9.44%; N 3.75%. Found: C 74.43%; H 9.44%; N 3.91%.

Example A3: 2,6-diethyl-2,3.6-trimethyl- 1 - (1 -phenyl-ethoxy) -piperidn-4-yl-ester of dodecanoic acid (Formula la, Compound 12)

In analogy to Example 1, 6.36 g (2 mmoles) of 2,6-diethyl-2, 3,6-trimethyl-1- (1-phenyl-ethoxy) -piperidin-4-ol were reacted with 4 , 38 g (2 mmol) of lauroyl chloride and 2.02 g (2 mmol) of triethylamine in toluene yielding 9.4 g (94%) of 2,6-diethyl-2,3,6-trimethyl-1 - (1-phenyl-ethoxy) -piperidin-4-yl-ester of dodecanoic acid in the form of a yellow liquid.

Elemental analysis calculated for C32H55NO3: C 76.59%; H 1 1.05%; N 2.79%. Found: C 76, 17%; H 1 1, 75%; N 2.69%.

Example A4: 2,2-diethyl-6,6-dimethyl-1- (1-phenyl-ethoxy) -piperidin-4-yl-ester of dodecanoic acid

(Formula IIa, Compound 1 2)

In analogy to Example 1, 6.1 g (2 mmoles) of 2,2-diethyl-6, 6-dimethyl-1- (1-phenylethoxy) -piperidin-4-ol (prepared as described in GB 2335190, Compound 110) with 4.38 g (2 mmol) of lauroyl chloride and with 2.02 g (2 mmol) of triethylamine in toluene to obtain 8.9 g (91%) of 2,2-diethyl-6 , 6-Dimethyl-1- (1-phenyl-ethoxy) -piperidin-4-yl-ester of dodecanoic acid in the form of a yellow liquid.

Elemental analysis calculated for C31 H53N03: C 76.33%; H 10.95%; N 2.87%. Found: C 75.57%; H 10.92%; N 2.90%.

Example A5: N- [2,6-diethyl-2,3,6-trimethyl-1 - (1 -phenyl-ethoxy) -piperidin-4-yl] -benzamide (Formula la, Compound 88)

A) N- [2.6-diethyl-2.3, 6-trimethyl-piperidin- 1 -oxyl-4-yl -benzamide

To a solution of 30.2 g (0.1 moles) of N- [2,6-diethyl-2,3,6-trimethyl-piperidin-4-yl] -benzamide (prepared according to US 4.191.683) in 100 ml of ethyl acetate, 38 g (0.2 moles) of 40% peracetic acid in acetic acid are added drop by drop under ice cooling. The mixture is stirred for 12 hours at room temperature. The red solution is washed with water, then with a 5% NaOH solution and again with water, is dried over MgSO4 and concentrated under vacuum. 31.2 g (98%) of N- [2,6-diethyl-2,3,6-trimethyl-piperidine-1-oxyl-4-yl] -benzamide are obtained in the form of an amorphous solid product.

B) 150 ml of ethylbenzene, 6.35 g (0.02 moles) of N- [2,6-diethyl-2,3,6-trimethyl-piperidin-1-oxyl-4-yl] are introduced into a photoreactor -benzamide and 12.7 g (0.087 moles) of t-butyl peroxide. The red solution is washed with nitrogen and subsequently irradiated with a mercury lamp under a nitrogen atmosphere at 20-25 ° C (pyrex glass). After 8 hours, the solution became colorless. The reaction mixture is concentrated in vacuo. The residue is purified by silica gel chromatography with hexane-ethyl acetate (9: 1) and is crystallized from hexane-toluene. 2.53 g (30%) of a colorless solid product are obtained with p. f. 112-147 ° C.

<1> H-NMR (300 MHz, CDCI3) 8.07-7.1 3 (m, 10 ArH), 6.0-5.85 (m, NH), 4.8-4.65 (m, 1H), 4.65-4.40 (m, 1H), 2.40-0.5 (m, 25H).

Example A6: 1 - [2,6-diethyl-2,3,6-trimethyl-1 - (1 -phenyl-ethoxy) -piperidin-4-yl] -3-ethyl-urea (Formula la, Compound 98)

A) 1 - [2,6-diethyl-2, 3.6-trimethyl-piperidin- 1 -oxyl-4-ill- 3-ethyl-urea

To a solution of 19.8 g (0.1 moles) of 2,6-diethyl-2,3,6-trimethyl-piperidine-4-yl-amine (prepared according to US 4,191,683) in 30 ml of toluene, 7.1 g (0.1 moles) of ethylisocyanate are added drop by drop. The mixture is stirred for 5 hours at room temperature and then concentrated under vacuum. The residue is dissolved in 60 ml of ethyl acetate and 40% peracetic acid is added slowly under cooling with ice water. The mixture is stirred for another 15 hours at room temperature. The red solution is washed with water, then with a 5% NaOH solution and again with water, is dried over MgSO4 and concentrated under vacuum. 25.65 g (90%) of 1- [2,6-diethyl-2, 3, 6-trimethyl-piperidin-1-oxyl-4-yl [-3-ethylurea are obtained in the form of a resinous material.

B) 1.08 g (0.038 mol) of 1- [2, 6-diethyl-2,3,6-trimethyl-piperidin-1-oxyl-4-yl] -3-ethyl-urea are reacted in analogy to Example 5 with ethylbenzene and with di-t-butyl peroxide. After chromatographic purification on hexane-ethyl acetate silica gel (3: 2) 0.7 g (47%) of 1- [2, 6-die t il-2, 3, 6- trimethyl- 1- (1- phenyl-ethoxy) -piperidin-4-yl] -3-ethyl-urea in the form of a colorless solid product.

<1> H-NMR (300 MHz, CDCI3) 7.4-5.2 (m, 5H), 4.8-4.6 (m, 1H), 4.5-3.9 (m, 3H) , 3.3-3.1 (m, 2H), 2.3-0.4 (m, 18H).

Example A7: 2- [2,6-diethyl-2,3,6-trimethyl- 1 - (1-phenyl-ethoxy) -piperidin-4-yl] -isoindole-1.3-dione (Formula la, Compound 111)

A) 2- [2.6-diethyl-2.3,6-trimethyl-piperidine-1-oxyl-4-yl] -isoindole-1,3-dione To a solution of 16.4 g (0.05 mol) of 2- [2, 6-diethyl-2, 3, 6-trimethyl-piperidin-4-yl] -isoindole-1,3-dione (prepared according to US 4,191,683) in 50 ml of 1,2-dichlorobenzene, are added, drop by drop, under ice cooling, 20.6 g (0.1 mol) of 40% peracetic acid in acetic acid. The mixture is stirred for 66 hours at room temperature. The red solution is washed with water, then with a 5% NaOH solution and again with water, is dried over MgSO4 and concentrated under vacuum. 16.28 g (95%) of 2- [2,6-diethyl-2,3,6-trimethyl-piperidine-1-oxyl-4-yl] -isoindole-1,3-dione are obtained in the form of a amorphous solid.

B) 1.54 g (0.0044 mol) of 2- [2,6-diethyl-2,3,6-trimethyl-piperidin-1-oxyl-4-yl] -isoindole-1,3- are reacted dione in analogy to Example 5 with ethylbenzene and with di-t-butyl peroxide. After chromatographic purification on silica gel with hexane-ethyl acetate (14: 1), 1.63 g (84%) of 2- [2,6-diethyl-2,3,6-trimethyl-1- (1-phenyl -ethoxy) -piperidin-4-yl] -isoindole-1,3-dione in the form of a colorless amorphous solid.

<1> H-NMR (300 MHz, CDCI3) 7, 8-7,1 (m, 9H), 4, 9-4, 5 (m, 1 H), 3, 3-0, 5 (m, 26H ). B) Polymerizations using compounds of formulas la or lla initiators / regulators General notes:

Solvents and monomers are distilled on a Vigreux column under an argon atmosphere or under vacuum, just before using them.

To remove oxygen, all polymerization reaction mixtures are subjected to an argon flow prior to polymerization and are placed under vacuum applying a freeze-thaw cycle. The reaction mixtures are then polymerized under an argon atmosphere.

At the start of the polymerization reaction, all starting substances are dissolved homogeneously.

The transformation is determined by removing unreacted monomers from the polymer at 80 ° C and 0.002 torr for 30 minutes, weighing the remaining polymer and subtracting the weight of the initiator.

GPC: It is operated using RHEOS 4000, an instrument of the company FLUX INSTRUMENTS. Tetrahydrofuran (THF) is used as a solvent and is pumped at a rate of 1 ml / min. Two chromatography columns are assembled together: type Plgel 5 μm C-mixed from POLYMER INSTRUMENTS, Shropshire, UK. Measurements are made at 40 ° C. The columns are calibrated with low polydispersibility polystyrenes having an Mn between 200 and 2,000,000 Dalton. The detection is carried out using a detector device ERC-7515A of the company ERCATECH AG at 30 ° C.

Example B1: Polymerization of n-butylacrylate using 1.5 mol% of compound 2 of formula la (Example A1) at 145 ° C

338 mg (0.94 mmol) of compound 2 and 8 g (62.4 mmol) of n-butyl acrylate were mixed in a 50 ml three-necked flask equipped with a thermometer, coolant and magnetic stirrer, and degassing. The clear solution obtained is heated under argon to 145 ° C and polymerization is carried out over the course of 5 hours. The reaction mixture is then cooled to 70 ° C. The remaining monomer is removed by evaporation under high vacuum. 6.64 g (83%) of the starting monomer reacted. A clear colorless viscous fluid is obtained.

Mn = 6700, Mw = 8700, PD = 1.3

Example B2: Polymerization of n-butylacrylate using 1.5 mol% of compound 2 of formula la (Example A1) at 130 ° C

338 mg (0.94 mmol) of compound 2 and 8 g (62.4 mmol) of n-butyl acrylate were mixed in a 50 ml three-necked flask equipped with a thermometer, coolant and magnetic stirrer, and degassing. The clear solution obtained is heated under argon to 130 ° C and polymerization is carried out over the course of 5 hours. The reaction mixture is then cooled to 70 ° C. The remaining monomer is removed by evaporation under high vacuum. 4.16 g (52%) of the starting monomer reacted. A clear colorless viscous fluid is obtained.

Mn = 4300, Mw = 5200, PD = 1.2

Example B3: Polymerization of n-butylacrylate using 1.2 mol% of compound 2 of formula la (Example A1) at 145 ° C

338 mg (0.94 mmol) of compound 2 and 10 g (78 mmol) of n-butyl acrylate were mixed in a 50 ml three-necked flask equipped with a thermometer, coolant and magnetic stirrer and 11 degassing was performed. The clear solution obtained is heated under argon to 145 ° C and polymerization is carried out over the course of 5 hours. The reaction mixture is then cooled to 70 ° C. The remaining monomer is removed by evaporation under high vacuum. 8 g (80%) of the starting monomer reacted. A clear colorless viscous fluid is obtained.

Mn = 8500, Mw = 11000, PD = 1.3

Example B4: Copolymerization of poly (n-butylacrylate) with N.N-dimethylaminoethylacrylate (DMAEA)

In a 50 ml three-necked flask equipped with a thermometer, refrigerant and magnetic stirrer, 6 g of poly (n-butylacrylates) of Example B3 and 6 g (42 mmoles) of N, N-dimethylaminoethylacrylate are mixed and the degassing. The clear solution obtained is heated under argon to 145 ° C and polymerization is carried out over the course of 3.5 hours. The residual monomer is removed by evaporation under high vacuum. 2.4 g (40%) of the starting monomer reacted. A viscous fluid of clear orange color is obtained.

Composition (NMR): 65% by weight of butylacrylate / 35% by weight of N, N-dimethylaminoethylacrylate Mn = 13000, Mw = 22150, PD = 1, 7

Claims (19)

CLAIMS 1. Compound of formula la or la in which Y is a radical is hydrogen, -COOH, -COO (C1-C4alkyl), -COO-phenyl, -COObenzyl, -C1-C8alkoxy, C1-C18alkyl, C2-C4alkenyl, C1-C18alkyl or C2-C4alkenyl substituted with OH, -COOH, - COO (C1-C4) alkyl, C2-C18alkyl, which can be interrupted with one or more oxygen atoms, cyclopentyl, cyclohexyl, cyclohexenyl, phenyl or unsubstituted naphthyl; or cyclopentyl, cyclohexyl, cyclohexenyl, phenyl or naphthyl which are substituted with C1-C4alkyl, -COOH or -COO- (C1-C4alkyl); R2 is hydrogen, C1-C18alkyl or R1 and R2, together with the nitrogen atom, form a 5-membered ring which it can have an unsaturated bond or it can be fused to a benzene ring; R3 is hydrogen or C1-C18alkyl; And X is selected from the group consisting of - (C5-C12) -3-cycloalkenyl, -CH2-phenyl, -CH3CH-phenyl, (CH3) 2C-phenyl, (C5-C6cycloalkyl) 2CCN, (CH3) 2CCN, -CH2CH = CH2, CH3CH-CH = CH2, (C1-C4alkyl) CR20-C (0) -phenyl, (C1C4) alkyl-CR20-C (0) - (C1-C4) alkoxy, (C1-C4) alkyl -CR2 - C (0) - (C1-C4) alkyl, (C1-C4) alkyl-CR20-C (0) -N-di (C1-C4) alkyl, (C1-C4) alkyl-CR20-C (0) - NH (C1-C4) alkyl, (C1-C4) alkyl-CR20-C (O) -NH2, wherein R20 is hydrogen or (C1-C4) alkyl; with the proviso that 2,6-diethyl-2,3,6-t rimethyl-1- (1-phenyl-ethoxy) -piperidine-4-ylester of benzoic acid is excluded. 2. Compound according to claim 1, wherein X is (3-cyclohexenyl), -CH2-phenyl CH3CH-phenyl or (CH3) 2C-phenyl. Compound according to claim 2, wherein X is CH3CH-phenyl. 4. Composed of formulas la or Ila, where Y is a radical of formula e R1 and R2 have the meaning as defined in claim 1. 5. Compound chosen by the group consisting of: 6. Compound chosen by the group consisting of: 7. Compound according to claim 5 or 6, chosen by the group consisting of: 8. A polymerizable composition comprising a) at least one ethylenically unsaturated monomer or oligomer, and b) a compound of formula la or la in which Y is a radical Ri is hydrogen, -COOH, -C00 (C1-C4alkyl), -COO-phenyl, -COObenzyl, C1-C8alkoxy, C1-C 18alkyl, C2-C4alkenyl, C1-C18alkyl or C2-C4alkenyl substituted with OH, -COOH, -C00 (C1-C4) alkyl, C2-C18alkyl which can be interrupted with one or more oxygen atoms, cyclopentyl, cyclohexyl, cyclohexenyl, phenyl or naphthyl unsubstituted or cyclopentyl, cyclohexyl, cyclohexenyl, phenyl or naphthyl which are substituted with C1 -C4alkyl, -COOH or with -C00- (C1-C4alkyl); R2 is hydrogen, C1-C18 alkyl or R1 and R2, together with the nitrogen atom, form a 5-membered ring which can have an unsaturated bond or can be condensed with a benzene ring; R3 is hydrogen or <C> 1 <_C> 18 alkyl; And X is selected from the group consisting of - (C5-C12) -3-cycloalkenyl, -CH2-phenyl, CH3CH-phenyl, (CH3) 2C-phenyl, (C5-C6cycloalkyl) 2CCN, (CH3) 2CCN, -CH2CH = CH2 , CH3CH-CH = CH2, (C1-C4alkyl) CR20-C (0) -phenyl, (C1-C4) alkyl-CR20-C (O) - (C1-C4) alkoxy, (C1-C4) alkyl-CR20 -C (0) - (C1-C4) alkyl, (C1-C4) alkyl-CR20-C (0) -N-di (C1-C4) alkyl, (C1-C4) alkyl-CR20-C (0) -NH (C1-C4) alkyl, (C3-C4) alkyl-CR20-C (O) -NH2, wherein R20 is hydrogen or (C1-C4) alkyl; with the proviso that 2, 6-diethyl-2, 3, 6-trimethyl-1- (1-phenyl-ethoxy) -piperidin-4-yl-ester of benzoic acid is excluded. 9. Composition according to claim 8, wherein the ethylenically unsaturated monomer or oligomer is selected from the group consisting of ethylene, propylene, n-butylene, i-butylene, styrene, substituted styrene, conjugated dienes, acrolein, vinyl acetate, vinylpyrrolidone, vinylimidazole, maleic anhydride, (alkyl) acrylic acid anhydrides, salts of an (alkyl) acrylic acid, (alkyl) acrylic esters, (meth) acrylonitriles, (alkyl) acrylamides, vinyl halides or vinylidene halides. 10. Composition according to claim 8, wherein the ethylenically unsaturated monomers are ethylene, propylene, n-butylene, i-butylene, isoprene, 1,3-butadiene, a-C5-C18alkene, styrene, a-methyl-styrene, p -met il-s tyrene or a compound of formula CH2 = C (Ra) - (C = Z) -Rb, in which Ra is hydrogen or C1-C4alkyl, Rb is NH2, 0- (Me <+>), glycidyl , C1-C18alkoxy unsubstituted, C2-C100alkoxy interrupted with at least one nitrogen and / or oxygen atom, or C1-C18alkoxy hydroxy-substituted, C1-C18alkylamino, di (C1-C18alkyl) unsubstituted amino, C1-C18alkylamino hydroxy- substituted or of (C1-C18alkyl) amino hydroxy-substituted ,, -0-CH2 -CH2-N (CH3) 2 or -0-CH2-CH2-N <+> H (CH3) 2 An-; An <-> is an anion of a monovalent organic or inorganic acid; Me is an atom of a monovalent metal or the ammonium ion; Z is oxygen or sulfur. 11. A composition according to claim 8, wherein the initiator compound is present in an amount ranging from 0.01 mol% to 30 mol%. 12. Process for preparing an oligomer, a cooligomer, a polymer or a copolymer (block or random) by free radical polymerization of at least one monomer or an ethylenically unsaturated oligomer, which consists in (co) polymerizing the monomer or monomers The oligomers in the presence of the initiator compound of formula la or 11a under the reaction conditions suitable for effecting the cleavage of the C-0 bond, so as to form two free radicals, the radical · Χ being able to initiate the polymerization. 13. Process according to claim 12, wherein the cleavage of the C-0 bond is carried out by heating and takes place at a temperature between 50 ° C and 160 ° C. 14. Polymer or an oligomer, having connected at least one initiator group -X and at least one group of an oxyamine of formula 1a or 11a according to claim 1. 15. A compound of formula Illa and IVa in which Y is a radical R1 is hydrogen, -C00H, -C00 (C1-C4alkyl), -COO-phenyl, -COObenzyl, -C1-C8alkoxy, C1-C18alkyl, 2 -C4alkenyl, C1-C18alkyl or C2-C4alkenyl substituted with OH, -COOH, -COO (C1-C4) alkyl, C2-C18alkyl, which can be interrupted with one or more atoms of oxygen, cyclopentyl, cyclohexyl, cyclohexenyl, phenyl or unsubstituted naphthyl; or cyclopentyl, cyclohexyl, cyclohexenyl, phenyl or naphthyl which are substituted with C1-C4alkyl, -COOH or -C00- (C1-C4alkyl); R2 is hydrogen, C1-C18alkyl or and R2, together with the nitrogen atom, form a 5-membered ring which can have an unsaturated bond or can be fused to a benzene ring; R3 is hydrogen or C1-C18alkyl; with the proviso that 2,6-diethyl -2, 3,6-trimethyl -4-lauroyloxy-hyperidine-1-oxyl, 2,6-diethyl-2,3,6-trimethyl-4-stearoyloxypiperidin-1-oxyl are excluded, 2,2-dimethyl-6, 6-diethyl-4-lauroyloxypiperidin-1-oxyl and 2,2-dimethyl-6,6-diethyl-4-stearoyloxypiperidin-1-oxyl. 16. A polymerizable composition comprising: a) at least one ethylenically unsaturated monomer or oligomer, and b) a compound of formula IIla or IVa e c) a source of free radicals capable of initiating a polymerization of ethylenically unsaturated monomers. 17. Process for preparing an oligomer, a cooligomer, a polymer or a copolymer (in blocks or with random distribution) by free radical polymerization of at least one ethylenically unsaturated monomer / oligomer, which consists in subjecting the composition according to claim 16 to a heat treatment or to an actinic radiation. 18. Use of a compound of formulas la or 11a according to claim 1 for the polymerization of ethylenically unsaturated monomers. 19. Use of a compound of formulas Illa or IVa according to claim 15 together with a source of free radicals for the polymerization of an ethylenically unsaturated monomer.